Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 36

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Fusarium head blight (FHB) incidence, and colonisation of grain by Fusarium species on winter wheat grown in organic, integrated, and conventional systems as well as in monoculture, were studied locally in Poland, from 2002 to 2010. Fusarium head blight incidence differed throughout the study years. It was found to occur the most where rainfall was highest and where rainfall was the most prolonged before, during, and after flowering of wheat. Fusarium head blight incidence was generally less on wheat grown organically than on wheat grown in other systems. In some years, FHB was noted more in monocultures than in other systems. Fusarium poae was the most common species of FHB populations in wheat kernels, followed by F. avenaceum and F. tricinctum. Other species which occurred more rarely or sporadically were: F. culmorum, F. equiseti, F. graminearum, F. langsethiae, F. oxysporum, and F. sporotrichioides. There were found to be significant effects of the cropping system on grain colonisation by Fusarium in some years. There was a positive correlation between FHB incidence and number of kernels colonised and damaged by Fusarium, in all four systems. Inferences were drawn concerning the effects of different procedures in different production systems and the possible value for controlling FHB.
In 2008 and 2010 Fusarium head blight (FHB) occurred sporadically and the number of ears with disease symptoms did not exceed 1%. An high increase of disease occurrence was observed at both locations in 2009. Significant differences were recorded between cultivars (1.0 to 35.0% of ears). The most susceptible cultivar to Fusarium head blightwas cultivar Tybalt followed by cultivars Partyzan, Bombona and Trappe. Different nitrogen fertilization significanty affected the disease occurrence only in case of cvs. Trappe, Nawra and Bombona.
The study was conducted on 50 single-hyphe R. solani isolates from potato tubers and sprouts grown in different regions of Poland and town of Bilitt (Norway). PCR assay showed that 45 isolates had the expected amplification product which classified them into group AG 3. Five isolates, which did not reveal the presence of this product were tested with SCAR primer sets designed for identification of AG 2-1 and AG 2-2 groups. PCR assay showed one isolate belonging to the AG 2-1 group, but no amplification product was produced for group AG 2-2.
The experiment conducted in 2002-2004 and located on experimental fields owned by the Institute of Soil Science and Plant Cultivation determined the effect of pre-germination of organically grown six cultivars (Bard, Bila, Baszta, Wolfram, Wawrzyn, Bzura) of potato seed tubers on occurrence of common scab (Streptomyces scabies) and dry rot of tubers (Fusarium spp.). Common scab was observed each year on all examined potato cultivars, but its intensity varied. The least number of symptoms showed Wawrzyn cv., while Wolfram cv. - the highest. Pre-germination of seed tubers significantly reduced both the percentage and disease index (DI) calculated for S. scabies, with the exception for Wawrzyn and Bard cvs. Symptoms of dry rot of tubers (Fusarium spp.) were noted in higher intensity in 2004 on Bzura cv. (5.8%) and significantly more symptoms were observed on pre-germinated potato tubers.
From 1999 to 2007, in separate experiments located in Mazury, Żuławy Wiślane and Powiśle, the presence of Fusarium head blight (FHB) of wheat as dependent on the forecrop and fungicide application was studied. During the experiments, FHB occurred in different intensities. High intensity was observed in the years 1999, 2001 and 2007. In other years it was low or only at trace levels. More disease symptoms were observed on the plots after wheat than after oilseed rape. Controlled treatments, applied during the period of shoot development, only limited the presence of FHB.
Badano wpływ systemu uprawy oraz zróżnicowanie gatunkowe grzybów zasiedlających sucho gnijące bulwy ziemniaka. Obiektem badań było 8 odmian ziemniaka uprawianego w systemie ekologicznym i integrowanym na polach doświadczalnych IUNG-PIB w Osinach k/Puław. Cztery tygodnie po zbiorach wykonano ocenę zdrowotności, a następnie z sucho gnijących bulw izolację grzybów. Objawy chorobowe występowały w różnym nasileniu. Najbardziej podatną na porażenie przez patogeny była odmiana Orlik. Najniższe porażenie odnotowano na odmianie Gracja. Stwierdzono również wpływ systemu uprawy na nasilenie objawów chorobowych. W ekologicznym systemie uprawy, niższe porażenie bulw było na odmianach Drop i Syrena, natomiast w integrowanym na odmianie Korona. Z sucho gnijących bulw pochodzących z ekologicznego systemu uprawy grzyby rodzaju Fusarium stanowiły 72,3% a z integrowanego 70,4% (głównie F. solani, F. oxysporum i F. sambucinum). Z innych grzybów najliczniej występowały Colletotrichum coccodes i Altemaria alternata (4,23%). Ponadto wyizolowano Gliocladium catenulatum, Rhizoctonia solani Arthrinium phaeospermum, Aureobasidium pullulans, Geotrichum candidum, Gliocladium spp., Penicillium spp., Phoma spp., Trichoderma spp.
Celem prowadzonych badań w latach 1997, 1998 i 2000 badań było określe­nie występowania Rhizoctonia solani na kiełkach, łodygach i bulwach oraz Streptomyces scabies i Fusarium spp. na bulwach ziemniaka uprawianego w systemie ekologicznym i konwencjonalnym. Stwierdzono, że w każdym roku nasilenie tych patogenów było stosunkowo duże. Jednak porażenie kiełków, pędów i bulw w okresie 3 lat w obu sposobach uprawy było na podobnym poziomie, a w jednym roku nawet wyższe w systemie ekologicznym. Świadczyć to może o braku mecha­nizmów obronnych w glebie tego systemu przed badanymi patogenami ziemnia­ka. Nie potwierdziły się powszechnie panujące przypuszczenia, że zaniechanie stosowania nawozów mineralnych i pestycydów wpływa korzystnie na rozwój sap­rofitycznych mikroorganizmów, które ewentualnie mogą zmniejszyć zagrożenie porażenia roślin przez gatunki patogeniczne.
Sclerotinia scletoriorum (Lib.) de Bary is a serious pathogen of carrots that can cause up to 50% losses of stored roots. Fungicides were found not to be completely effective for its control and due to residues they are not permitted for the use in storage. Biological control agents such as Pythium oligandrum may be a chance. The aim of research was to determine the level of carrot infection with S. sclerotiorum during few-month storage with qPCR and the potential control ability of this pathogen by Polyversum WP containing oospores of P. oligandrum. We analyzed carrot roots in combinations treated with Polyversum WP on the field, fumigated with biopreparation before storage and untreated control. S. sclerotiorum developed on carrots treated and untreated with Polyversum WP. During the storage, pathogen was isolated from 44.4% samples and P. oligandrum from 53.8% ones, respectively in the range from 0.0001 to 130 200.0; pg and from 0.004 to 0.3440 pg per sample. The number of roots with S. sclerotiorum and degree of their infection increased with prolonged storage. Analyses suggest that Polyversum WP may potentially limit the growth of S. sclerotiorum.
The aim of the study was the effect of different chemical protection of winter wheat on occurrence of fungal diseases of stem base, leaves and yield as well. In 1999-2001 cultivars Roma and Kobra were tested in Lisewo and Wielgłowy in northern Poland. There was one fungicide treatment with kresoxim-methyl and epoxyconazole during phase 39—49 and two treatments, first with kresoxim-methyl + epoxyconazole in phase 32 and the second with tridemorf + epoxyconazole in phase 51-55. In 2002-2004 the experiment was continued in Wielgłowy on cultivar Kobra with protection combinations as follows: first treatment with kresoxim-methyl + epoxyconazole in phase 39-49, and the next ones with tridemorf + epoxyconazole or dimoksystrobine + epoxyconazole in phase 51-55. The highest infection was observed on cv. Kobra. Among pathogens isolated from infected stem bases, Fusarium spp. predominated, while Rhizoctonia spp. and Mollisia yallundae were less numerous. Powdery mildew was observed in relatively low or trace intensity, but complex of necrotic spots on leaves was noticed in high intensity. High occurrence of Mycosphaerella graminicola,. Phaeosphaeoria nodorum and Pyrenophora tritici-repentis as well as Fusarium spp. was observed. Fungicide treatments were very effective in reducing occurrence of the investigated pathogens. The area of upper leaves without disease symptoms (GLA) was significantly higher in combinations with fungicides.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.